Question

The products A and B in the following reactions, respectively, are:

• A. CH$_3$-CH$_2$-CH$_2$-NO$_2$, CH$_3$-CH$_2$-CH$_2$-NC
• B. CH$_3$-CH$_2$-CH$_2$-ONO, CH$_3$-CH$_2$-CH$_2$-CN
• C. CH$_3$-CH$_2$-CH$_2$-ONO, CH$_3$-CH$_2$-CH$_2$-NC
• D. CH$_3$-CH$_2$-CH$_2$-NO$_2$, CH$_3$-CH$_2$-CH$_2$-CN

Hint:

AgX reagents (where X can be NO$_2$ or CN) are often used for nucleophilic substitutions in organic synthesis to introduce nitro or cyano groups respectively.

Answer 1

The Correct Option is C

When an alkyl halide reacts with $ AgNO_2 $, the product is a nitroalkane ($ R-NO_2 $).
This is because silver nitrite is a covalent compound, and the nitrogen atom donates the electron pair to form a covalent bond with the alkyl group.

When an alkyl halide reacts with $ AgCN $, the product is an alkyl isocyanide ($ R-NC $).
This happens because silver cyanide is predominantly covalent. The carbon atom is more electronegative than silver, so it prefers to form a bond with silver. The nitrogen atom has a lone pair of electrons, which attacks the carbon atom of the alkyl halide, leading to the formation of an isocyanide.

In the given reactions:

$$ CH_3-CH_2-CH_2-Br \xrightarrow{AgNO_2} CH_3-CH_2-CH_2-NO_2 \quad (A) $$ $$ CH_3-CH_2-CH_2-Br \xrightarrow{AgCN} CH_3-CH_2-CH_2-NC \quad (B) $$

Therefore:

• A is $ CH_3-CH_2-CH_2-NO_2 $
• B is $ CH_3-CH_2-CH_2-NC $

Final Answer:
The final answer is $ CH_3 - CH_2 - CH_2 - NO_2,\ CH_3 - CH_2 - CH_2 - NC $.